Fuel injection system employing the second time differential of pressure or air flow rate

Abstract

Synchronous fuel injection amount of injected from a fuel injector in synchronization with rotation of an engine is controlled in relation to the second time differential of either the intake pipe pressure or intake flow rate.

What is claimed is: 
     
       1. An electronically controlled fuel injection system to inject fuel from a fuel injector to an intake system having an intake pipe pressure and an air flow rate comprising: means for detecting a quantity X equal to one of said intake pipe pressure and an air flow rate with respect to time;   means for determining a basic fuel injection amount as a function of X;   means for detecting a second differential d 2  X/dt 2  of X with respect to time; and   means for increasing synchronous fuel injection in relation to said second differential.   
     
     
       2. An electronically controlled fuel injection system as defined in claim 1, wherein said differential detecting means includes means for detecting said second differential in a predetermined cycle, and wherein said fuel injection increasing means includes means for carrying out a first increase of synchronous acceleration fuel injection if said second differential exceeds a first predetermined value and means for carrying out an increase of synchronous acceleration fuel injection in the second and succeeding cycles if said second differential exceeds a second predetermined value. 
     
     
       3. A system as defined in claim 2 wherein said means for calculating d 2  X/dt 2  comprises means for calculating an amount ΔX of change of X per a first predetermined time and for calculating as d 2  X/dt 2  an amount ΔΔX of change of ΔX per a second predetermined time. 
     
     
       4. A system as defined in claim 3 wherein the increase of synchronous fuel injection when ΔΔX is greater than said first predetermined value is different than when ΔΔX is greater than said second predetermined value. 
     
     
       5. A system as defined in claim 3, wherein said first predetermined value is greater than said second predetermined value. 
     
     
       6. A system as defined in claim 1 wherein an increase of a synchronous fuel injection according to d 2  X/dt 2  decreases by a predetermined amount in succeeding cycles.